Rozhen Observation Calendar

Which nights are best for a target over the coming weeks. The astronomy mark (darkness × altitude × Moon) is computed for every night; the weather and the overall mark exist only where Open-Meteo has a forecast (the next four days) or ERA5 history (past nights) — the rest is honestly blank.

Best nights for HD 189733: 10-20 (100), 10-21 (100), 10-22 (96), 11-08 (93), 11-07 (92) — by astronomy; check the weather when the night is within four days.

2028-10-20astronomy score per night — click a bar for that night2028-11-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-10-20 Fri	100	—	unknown	20:05–00:30 (good, 4.42 h)	71.1° 19:25	10.06	11%	72.4°
2028-10-21 Sat	100	—	unknown	20:05–00:25 (good, 4.33 h)	71.1° 19:20	10.1	19%	62.5°
2028-10-22 Sun	96	—	unknown	20:05–00:25 (good, 4.33 h)	71.1° 19:15	10.14	28%	53.8°
2028-10-23 Mon	87	—	unknown	20:05–00:20 (good, 4.25 h)	71.1° 19:15	10.18	37%	46.8°
2028-10-24 Tue	68	—	unknown	20:00–00:15 (good, 4.25 h)	71.1° 19:10	10.22	47%	42.1°
2028-10-25 Wed	54	—	unknown	20:00–23:45 (good, 3.75 h)	71.1° 19:05	10.26	57%	40.2°
2028-10-26 Thu	43	—	unknown	20:00–21:35 (good, 1.58 h)	71.1° 19:00	10.3	66%	41.2°
2028-10-27 Fri	36	—	unknown	20:00–00:20 (marginal, 4.33 h)	71.1° 18:55	10.33	75%	45.0°
2028-10-28 Sat	33	—	unknown	19:55–00:10 (marginal, 4.25 h)	71.1° 18:55	10.37	82%	50.7°
2028-10-29 Sun	32	—	unknown	18:55–23:00 (marginal, 4.08 h)	71.1° 17:50	10.41	89%	57.8°
2028-10-30 Mon	34	—	unknown	18:55–22:55 (marginal, 4.0 h)	71.1° 17:45	10.45	94%	65.9°
2028-10-31 Tue	39	—	unknown	18:55–19:50 (good, 0.92 h)	71.1° 17:40	10.48	98%	74.7°
2028-11-01 Wed	46	—	unknown	18:50–20:35 (good, 1.75 h)	71.1° 17:35	10.52	100%	83.8°
2028-11-02 Thu	55	—	unknown	18:50–21:25 (good, 2.58 h)	71.1° 17:35	10.56	100%	93.2°
2028-11-03 Fri	66	—	unknown	18:50–22:10 (good, 3.33 h)	71.1° 17:30	10.59	98%	102.7°
2028-11-04 Sat	75	—	unknown	18:50–22:15 (good, 3.42 h)	71.1° 17:25	10.63	94%	112.0°
2028-11-05 Sun	89	—	unknown	18:50–22:20 (good, 3.5 h)	71.1° 17:20	10.66	88%	120.9°
2028-11-06 Mon	91	—	unknown	18:45–22:15 (good, 3.5 h)	71.1° 17:20	10.69	80%	129.0°
2028-11-07 Tue	92	—	unknown	18:45–22:15 (good, 3.5 h)	71.1° 17:15	10.73	71%	135.4°
2028-11-08 Wed	93	—	unknown	18:45–22:15 (good, 3.5 h)	71.1° 17:10	10.76	61%	139.3°
2028-11-09 Thu	91	—	unknown	18:45–22:10 (good, 3.42 h)	71.1° 17:05	10.79	50%	139.7°
2028-11-10 Fri	90	—	unknown	18:45–22:10 (good, 3.42 h)	71.1° 17:00	10.82	38%	136.1°
2028-11-11 Sat	89	—	unknown	18:40–22:05 (good, 3.42 h)	71.1° 17:00	10.86	28%	129.4°
2028-11-12 Sun	87	—	unknown	18:40–22:00 (good, 3.33 h)	71.1° 16:55	10.89	18%	120.5°
2028-11-13 Mon	86	—	unknown	18:40–21:55 (good, 3.25 h)	71.1° 16:50	10.92	10%	110.2°
2028-11-14 Tue	85	—	unknown	18:40–21:50 (good, 3.17 h)	71.1° 16:45	10.95	4%	99.2°
2028-11-15 Wed	83	—	unknown	18:40–21:50 (good, 3.17 h)	71.1° 16:40	10.97	1%	88.0°
2028-11-16 Thu	81	—	unknown	18:40–21:45 (good, 3.08 h)	71.1° 16:40	11.0	0%	77.0°
2028-11-17 Fri	79	—	unknown	18:40–21:40 (good, 3.0 h)	71.1° 16:35	11.03	2%	66.5°
2028-11-18 Sat	79	—	unknown	18:35–21:35 (good, 3.0 h)	71.1° 16:30	11.06	7%	57.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-10-20&days=30"
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&days=30&format=csv" -o m31-calendar.csv

One row per night: score_astronomy always, score_weather / score only where a forecast or history exists (null otherwise, with weather_source saying which), best window, dark hours, Moon illumination and separation, transit. 7–60 nights. Errors: 400 with invalid_date or target_unresolved. Results are cached for six hours; calculation version 2026-10-10.1.